CDSEM rapid measurement method and device, medium, program product and terminal

Abstract

According to the CDSEM rapid measurement method and device, the medium, the program product and the terminal, optimization of the CDSEM measurement process is achieved through the technical means of introducing measurement position compensation and presetting the automatic focusing voltage value. The method comprises the following specific steps: acquiring coordinates of a plurality of points to be measured, generating a measurement sequence based on the coordinates, and carrying out multiple goods passing operations. And in each goods passing operation, the offset errors and the current focusing parameters of all the measurement points are recorded, the optimal compensation error and the optimal focusing parameter are generated, and the optimal compensation error and the optimal focusing parameter are applied to coordinate compensation and simplified measurement operation. The efficiency of the CDSEM measuring system is remarkably improved, and particularly, the requirement for rapid and accurate measurement is effectively met in the mass production stage. Therefore, the repeated calibration and focusing steps in the traditional CDSEM measurement process are avoided, the measurement time is greatly reduced, the wafer throughput of a CDSEM machine table is greatly improved, and the capacity of the machine table is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor measurement, and in particular to a CDSEM rapid measurement method, device, medium, program product and terminal. Background Art

[0002] In today's semiconductor industry, with the continuous upgrading of technology and the continuous increase in market demand for high-performance chips, the requirements for chip size and accuracy are becoming increasingly stringent. As an important measurement tool, the critical dimension scanning electron microscope (CDSEM) is responsible for measuring key dimensions during the wafer manufacturing process to ensure that each chip meets the design specifications, thereby ensuring product quality and performance.

[0003] The existing CDSEM measurement process includes four steps: alignment, calibration, focusing and measurement. Among them, the three steps of calibration, focusing and measurement need to be performed cyclically for each target point to be measured. Among them, the alignment step is used to ensure the coordination of the optical microscope (OM) and the scanning electron microscope (SEM) lenses so that the wafer coordinates coincide with the machine coordinate system. The calibration step is used to eliminate the position deviation caused by electron beam drift and worktable movement to ensure that the error is controlled below 20 nanometers. The focusing step is used to ensure the imaging quality by finding similar patterns and automatically adjust the focal length to optimize the measurement conditions. The measurement step is used to perform accurate and efficient measurements in the measurement box (MB) to achieve high-precision measurements. Although the process of the prior art can effectively guarantee the accuracy and consistency of the measurement, since the coordinates of each target in the measurement area are fixed, the influence of the machine movement error and electron beam drift is not considered. The traditional method requires separate calibration and focusing for each target. This makes the measurement process extremely time-consuming, significantly increases the measurement time of each wafer, and reduces the overall measurement efficiency. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of this application is to provide a CDSEM fast measurement method, device, medium, program product and terminal to solve the problem that the existing CDSEM measurement process is cumbersome and time-consuming, and the deviation correction is limited to a specific coordinate system, without considering the machine movement error and electron beam drift error, thereby affecting the efficiency and accuracy under high throughput requirements. .

[0005] To achieve the above-mentioned purpose and other related purposes, the first aspect of the present application provides a method of CDSEM rapid measurement method, including: obtaining coordinates of multiple points to be measured at a measurement site, and generating a corresponding measurement sequence based on the coordinates of the points to be measured; performing multiple cargo transfer operations according to the measurement sequence, and collecting the offset errors of all measurement points in the current cargo transfer operation and the corresponding focus parameters during measurement in each cargo transfer operation; generating an optimal compensation error and an optimal focus parameter based on the collected offset errors of all cargo transfer operations and the corresponding focus parameters during measurement; performing a coordinate compensation operation on the points to be measured according to the optimal compensation error, and calling the optimal focus parameter to perform a simplified measurement operation on the coordinates of the points to be measured after the coordinate compensation operation.

[0006] In some embodiments of the first aspect of the present application, the process of collecting the offset errors and corresponding optimal focusing parameters of the coordinates of all the points to be measured in the current cargo transfer operation in each cargo transfer operation includes: performing a machine error correction operation and a pattern recognition operation on the coordinates of the current point to be measured to generate a calibration point coordinate; calculating and generating a PR difference based on the calibration point coordinates and the coordinates of the current point to be measured; performing an autofocus operation on the calibration point coordinates, and extracting the autofocus parameters after the autofocus operation; based on the measurement formula, focusing the electron beam to the MB area of ​​the current coordinates of the point to be measured, and calculating the MB difference used to characterize the error between the MB area and the center of the coordinates of the point to be measured.

[0007] In some embodiments of the first aspect of the present application, based on the collected offset errors of all cargo transfer operations and the corresponding focus parameters during measurement, the process of generating the optimal compensation error and the best focus parameters includes: for each coordinate of the point to be measured, based on the feature point selection algorithm, according to the collected PR difference and MB difference of all cargo transfer operations, calculating the PR compensation value and the MB compensation value to generate the optimal compensation error; according to the PR compensation value, the PR difference of all cargo transfer operations and the autofocus parameters, calculating and generating the optimal focus parameters.

[0008] In some embodiments of the first aspect of the present application, the process of performing coordinate compensation operation on the measurement point to be measured according to the optimal compensation error includes: substituting the PR compensation value, the MB compensation value and the coordinates of the measurement point to be measured into the parameter compensation formula to generate a compensated measurement point.

[0009] In some embodiments of the first aspect of the present application, the process of calling the optimal focus parameters to perform a simplified measurement operation on the coordinates of the measurement point to be measured after the coordinate compensation operation includes: performing OM calibration and SEM calibration operations on the measurement site; performing a measurement operation on the coordinates of the measurement point to be measured after the coordinate compensation operation based on the optimal focus parameters, and measuring the coordinates of the measurement point to be measured after the coordinate compensation operation to generate a final measurement result.

[0010] In some embodiments of the first aspect of the present application, after the coordinates of the points to be measured after the coordinate compensation operation are simplified, the following operation is also performed: in response to the occurrence of MB position loss during the measurement of multiple consecutive points to be measured, the conventional measurement operation is re-executed on the current point to be measured, and it is determined whether the measurement is successful; if the conventional measurement operation is unsuccessful after re-execution, multiple cargo transfer operations are re-executed according to the measurement sequence, and in each cargo transfer operation, the offset errors of all measurement points in the current cargo transfer operation and the corresponding focus parameters during measurement are collected; based on the offset errors of all the collected cargo transfer operations and the corresponding focus parameters during measurement, the optimal compensation error and the optimal focus parameters are re-generated; and the coordinate compensation operation is performed on the points to be measured according to the optimal compensation error generated again, and the simplified measurement operation is performed on the coordinates of the points to be measured after the coordinate compensation operation according to the optimal focus parameters generated again.

[0011] To achieve the above-mentioned purpose and other related purposes, the second aspect of the present application provides a CDSEM rapid measurement device, including: a data acquisition module: used to obtain the coordinates of multiple points to be measured at the measurement site, and generate a corresponding measurement sequence based on the coordinates of the points to be measured; a parameter compensation module: used to perform multiple cargo transfer operations according to the measurement sequence, and in each cargo transfer operation, collect the offset errors of all measurement points in the current cargo transfer operation and the corresponding focus parameters during measurement; based on the collected offset errors of all cargo transfer operations and the corresponding focus parameters during measurement, generate an optimal compensation error and an optimal focus parameter; a simplified measurement module: used to perform a coordinate compensation operation on the points to be measured according to the optimal compensation error, and call the optimal focus parameter to perform a simplified measurement operation on the coordinates of the points to be measured after the coordinate compensation operation.

[0012] To achieve the above-mentioned purpose and other related purposes, the third aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, and the computer program implements the CDSEM rapid measurement method when executed by a processor.

[0013] To achieve the above-mentioned purpose and other related purposes, the fourth aspect of the present application provides a computer program product, which includes a computer program code. When the computer program code runs on a computer, the computer implements the CDSEM rapid measurement method.

[0014] To achieve the above-mentioned purpose and other related purposes, the fifth aspect of the present application provides an electronic terminal, including a memory, a processor and a computer program stored in the memory; the processor executes the computer program to implement the CDSEM rapid measurement method.

[0015] As described above, the CDSEM rapid measurement method, device, medium, program product and terminal of the present application have the following beneficial effects: First, by reducing the focusing steps, the measurement process is optimized, the detection time is greatly shortened, and the production efficiency is increased. Secondly, since the process is stable in the mass production stage and the wafer states of the same site are similar, consistent measurement accuracy is maintained through precise focusing parameters, thereby improving the consistency of product quality. In addition, the invention also reduces the need for physical adjustment of the equipment and reduces equipment wear and maintenance costs caused by frequent calibration and focusing. Furthermore, the present invention can be applied to a variety of measurement scenarios and has high flexibility and adaptability, thereby significantly improving the repeatability and stability of the process in a large-scale production environment, reducing the scrap rate, and bringing substantial cost advantages and competitiveness improvements to manufacturing companies. In general, the invention not only improves the operating efficiency of CDSEM, but also has a positive impact on the entire semiconductor manufacturing process chain through a more accurate measurement process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The figure shows the flow chart of the prior art of CDSEM rapid measurement of the present application.

[0017] Figure 2 A flow chart of an embodiment of the CDSEM rapid measurement method of the present application is shown.

[0018] Figure 3 A flow chart of another embodiment of the CDSEM rapid measurement method of the present application is shown.

[0019] Figure 4 A structural schematic diagram of an embodiment of a CDSEM rapid measurement device of the present application is shown.

[0020] Figure 5 A structural schematic diagram of an embodiment of a CDSEM rapid measurement terminal of the present application is shown. DETAILED DESCRIPTION

[0021] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0022] Before further describing the present invention in detail, the nouns and terms involved in the embodiments of the present invention are explained. The nouns and terms involved in the embodiments of the present invention are applicable to the following interpretations:

[0023] <1> CDSEM measurement: CDSEM is a scanning electron microscope specifically designed to measure critical dimensions in semiconductor devices and nanostructures. Its main functions include high-resolution imaging and dimensional measurement, allowing engineers to accurately analyze circuit patterns, feature widths and spacing. CDSEM can provide measurement accuracy up to sub-nanometer level and is usually equipped with automated software to support fast and accurate measurement processes.

[0024] <2> Cargo handling: Cargo handling refers to the transfer and handling steps of products or samples during the measurement process. This process includes the correct placement, alignment and data reading of samples to ensure the reliability and accuracy of the measurement results. Cargo handling requires strict adherence to standard operating procedures to avoid damage to samples during transportation or handling.

[0025] <3> Focus parameters: Focus parameters usually include the distance between the sample and the electron beam focus, the aperture setting of the electron beam, and the contrast setting of the image. Adjustment of these parameters can optimize imaging conditions, enhance the visualization of the pattern, and ensure measurement accuracy.

[0026] <4> Pattern Recognition PR: Pattern Recognition (Pattern Recognition) By using image processing technology, the software can detect, classify and measure different structures and defects on the surface of the sample. This process is very important in quality control and verification because it ensures that semiconductor products meet design specifications.

[0027] <5> Auto Focus AF: Auto Focusing uses an automated system to dynamically adjust the focus of the electron beam to ensure optimal image clarity. Auto Focus technology can reduce errors caused by human operation and improve measurement speed and efficiency. Modern CDSEM systems are usually equipped with advanced sensors and algorithms to achieve real-time and efficient focus adjustment.

[0028] <6> Measurement Box: The measurement box is a specific area selected during the measurement process for dimensional measurement and defect assessment. The definition of the measurement box is usually based on the specific geometry of the sample and the target area to be measured. By accurately selecting the appropriate measurement box on the sample surface, it can ensure that the measurement results are more representative, accurate and repeatable, thereby obtaining reliable analysis results.

[0029] <7> Electron beam bombardment: By focusing a high-energy electron beam onto the sample surface, the sample is stimulated to emit secondary electrons. The measurement of these secondary electrons can generate high-resolution images of the sample and provide data for subsequent surface analysis. The energy and focus position of the electron beam bombardment have a significant impact on the quality of the image and the measurement results.

[0030] <8> Lossy measurement: Lossy measurement refers to techniques that may cause changes or damage to the sample structure during the measurement process. This type of measurement usually affects the subsequent use or analysis of the sample, so it does require a trade-off when designing the measurement experiment to ensure that sufficient measurement data is obtained.

[0031] <9> OM calibration: OM (optical microscope) calibration refers to the adjustment and verification of the microscope system to ensure that the data acquired during the optical imaging process can accurately reflect the actual state of the sample, including the image resolution, magnification and other imaging characteristics. This process is critical for repeatability and consistency measurements.

[0032] <10> SEM Calibration: SEM (Scanning Electron Microscope) calibration involves precise adjustment of the CDSEM to ensure the accuracy of the critical dimensions it measures. The calibration process involves comparing the measurement results with known standards to adjust multiple parameters of the instrument, such as the voltage, focus and scanning speed of the electron beam, to ensure that industry standards and technical specifications are met.

[0033] <11> Electron beam drift: Electron beam drift refers to the small, unstable movement of the electron beam focus position during long-term measurement or operation. This drift phenomenon may cause image blur and even affect the measurement accuracy. Therefore, engineers need to regularly monitor and adjust the system to ensure the stability of the electron beam.

[0034] <12> BSL (Baseline) cargo handling: BSL (Baseline) cargo handling refers to the inspection and processing of samples against baseline standards. This process ensures that each sample must meet the predetermined baseline requirements in terms of performance and quality, thereby ensuring the consistency and reliability of the product. This operation is crucial to preventing potential quality problems and can improve the efficiency and yield of the production process.

[0035] Figure 1 The figure shows the flow chart of CDSEM measurement method in the prior art. Figure 1As shown, first, the wafer is aligned by OM and SEM to ensure that its coordinate system coincides with the equipment; for each target point to be measured, PR calibration is performed near its area to eliminate the position deviation caused by electron drift and stage movement. The PR calibration is usually performed on a selected larger pattern with an optimal distance of 3 to 10 microns. Subsequently, the autofocus AF function is used to find an area with a similar shape near the measurement position for autofocus operation to ensure clear imaging and determine the working voltage of the optimal focal plane. Finally, since the SEM mirror will also produce deviations when it moves to the measurement position, a small-grained image-based position calibration (PR) is performed again before the formal measurement to remove the errors caused by stage and electron beam drift, and to ensure that the measurement position is in the center of the area to be measured. The measurement is performed within a certain area, and the measured area is called MB. Repeat the above three steps of calibration, focusing, and measurement for the remaining targets to be measured. Although this process can effectively ensure measurement accuracy and consistency, the traditional measurement method does not take into account equipment movement errors and electron beam drift. It requires each target to be calibrated and focused individually, which increases the measurement time and reduces the overall efficiency.

[0036] To facilitate understanding of the embodiments of the present application, first Figure 2 Detailed description. Figure 2 The flowchart of a CDSEM rapid measurement method in an embodiment of the present invention is shown. The CDSEM rapid measurement method in this embodiment mainly includes the following steps:

[0037] Step S21: acquiring coordinates of a plurality of points to be measured at the measurement site, and generating a corresponding measurement sequence based on the coordinates of the points to be measured.

[0038] In one embodiment of the present invention, the coordinates of multiple points to be measured are represented in a measurement site in the mass production stage. Each shot needs to monitor m targets and perform n bombardment tests in total, so the total number of target measurement points is m*n. In the measurement site of this embodiment, multiple production batches (Lot) are usually included. Each production batch is carried by a loading box (Foup), and the standard configuration is 25 wafers (Wafer), collectively referred to as a lot. During the measurement process, sampling inspection is performed from multiple wafers, and the sampling inspection method includes sampling inspection of odd-numbered wafers and sampling inspection of even-numbered wafers. Exemplarily, the measurement scheme can adopt 10 bombardment tests (Shot), in which each bombardment test is measured for 2 or 5 targets (Target).

[0039] In one embodiment of the present invention, the coordinates of the points to be measured refer to the specific locations on the wafer surface that are pre-specified for measurement and are planned according to the manufacturing process and design requirements. The coordinates of the points to be measured include the X and Y positions of each target area, and in some embodiments, also involve the height information of the Z axis to ensure accurate positioning.

[0040] In one embodiment of the present invention, the process of generating a corresponding measurement sequence based on the coordinates of the points to be measured includes: based on the principle of minimum movement of the electron beam, generating a corresponding measurement sequence through the coordinates of the points to be measured. The specific steps include: first, collecting the coordinate information of all the points to be measured and calculating the distance between each point. Secondly, using the optimization algorithm to determine the optimal measurement sequence to reduce the moving distance and time of the electron beam between the points to be measured. After that, generate the optimal path, plan the moving trajectory of the electron beam, and formulate a detailed measurement plan, including the measurement time and measurement parameters of each point. Finally, verify the generated measurement sequence to ensure its feasibility and effectiveness in actual operation. Exemplarily, the optimization algorithm includes: greedy algorithm, dynamic programming, genetic algorithm. It is worth noting that the advantage of generating a measurement sequence based on the principle of minimum movement of the electron beam is that it significantly reduces the moving distance of the electron beam between the points to be measured, thereby improving the measurement efficiency and reducing the measurement time, which will help reduce the errors caused by the drift of the machine and the electron beam.

[0041] It should be explained that in the CDSEM (metrology scanning electron microscope) scenario, electron beam drift refers to the unexpected deviation of the electron beam relative to the standard position when performing operations such as line width measurement. Electron beam drift may be caused by a variety of factors, such as environmental vibration, thermal expansion of the equipment due to temperature changes, unstable focusing of the electron beam itself, or electromagnetic interference, which affects the measurement accuracy and causes errors in the measurement results of key dimensions such as line width.

[0042] Step S22: performing multiple cargo transfer operations according to the measurement sequence, and collecting the offset errors of all measurement points in the current cargo transfer operation and the corresponding focus parameters during measurement in each cargo transfer operation; generating the optimal compensation error and the optimal focus parameters based on the collected offset errors of all cargo transfer operations and the corresponding focus parameters during measurement.

[0043] In one embodiment of the present invention, the cargo handling operation refers to the Baseline (BSL) cargo handling operation, which is intended for the transportation and handling of baseline samples or standard parts in semiconductor manufacturing or related fields. These samples serve as reference standards for other production processes and equipment performance, and must follow specific processes and standards to ensure their accuracy and completeness. Specifically, the BSL cargo handling operation includes the sample preparation stage, loading and transportation stage, unloading and storage stage, which involves ensuring that the samples meet the standards, adopting appropriate packaging and transportation conditions to prevent damage, and delivering the samples safely and maintaining a suitable storage environment. Through the technical means of parameter compensation and pre-focusing of the present invention, the efficiency of the BSL cargo handling operation can be improved, while ensuring quality control and consistency in the production process.

[0044] In one embodiment of the present invention, the process of collecting the offset errors and corresponding optimal focusing parameters of the coordinates of all the points to be measured in the current cargo transfer operation in each cargo transfer operation includes: performing a machine error correction operation and a pattern recognition operation on the coordinates of the current point to be measured to generate a calibration point coordinate; calculating and generating a PR difference based on the calibration point coordinates and the coordinates of the current point to be measured; performing an autofocus operation on the calibration point coordinates, and extracting the autofocus parameters after the autofocus operation; based on the measurement formula, focusing the electron beam to the MB area of ​​the current coordinates of the point to be measured, and calculating the MB difference used to characterize the error between the MB area and the center of the coordinates of the point to be measured.

[0045] In one embodiment of the present invention, the process of performing a machine error correction operation and a pattern recognition (PR) operation on the coordinates of the current point to be measured includes two parts: machine error acquisition and pattern recognition operation. Among them, the machine error represents the offset error caused by the movement of the machine, and is automatically recorded and analyzed by the machine. Specifically, the machine records the offset between the actual position and the expected position of the electron beam at different positions through a sensor, and establishes a machine error model to quantify the offset error caused by the movement process, and accurately records and analyzes the offset through standardized tests to ensure the identification of systematic offset errors and random offset errors.

[0046] In one embodiment of the present invention, the pattern recognition (PR) process is mainly used to accurately determine the position and offset of the point to be measured before measurement to meet the requirements of high-precision measurement. The process of pattern recognition (PR) includes the following steps: First, the area closest to the target pattern is extracted by an image recognition algorithm to generate the coordinates of the PR area. The steps of the image recognition algorithm include: graying, edge detection and feature extraction operations to identify key features and shapes in the area to be measured. Subsequently, the extracted features are matched with the target pattern, and the coordinates of the area closest to the target pattern are generated by a matching algorithm, so as to calculate the offset between the actual position and the expected position of the target pattern, and generate the calibration point coordinates. The matching algorithm includes but is not limited to: template matching, SIFT (scale invariant feature transform), SURF (accelerated robust feature), ORB (direction-preserving binary feature), KNN (K nearest neighbor algorithm), RANSAC (random sampling consensus algorithm).

[0047] In one embodiment of the present invention, the process of performing an autofocus operation on the calibration point coordinates and extracting the autofocus parameters after the autofocus operation is mainly performed on the extracted PR area, wherein the PR area contains the calibration point coordinates. The steps of the autofocus operation include: starting the autofocus AF function for the calibration point coordinates to adjust the optimal focus of the selected PR area. Specifically, through SEM calibration, a high-resolution image of the current PR area is obtained, and the image clarity and contrast are evaluated using an image processing algorithm. And according to the results of the focus evaluation, the focal length and operating voltage are automatically adjusted until the image reaches the optimal clarity. Furthermore, after the autofocus is completed, the current autofocus parameters, including the optimal focal plane and the operating voltage, are recorded, and the focus parameters are used as pre-focus parameters for subsequent BSL cargo handling operations to improve the efficiency of the entire CDSEM measurement.

[0048] In one embodiment of the present invention, the autofocus operation is optimized by moving the electron beam focused on the PR area to the peripheral area of ​​the point to be measured. The shape of the peripheral area is consistent with the area of ​​the point to be measured, effectively simulating the characteristics of the area to be measured. When autofocusing in the peripheral area, the system can evaluate the optimal focusing conditions for the point to be measured. This process ensures that the optimal focusing parameters are accurately estimated without causing any measurement loss to the point to be measured, thereby ensuring that the electron beam achieves the highest imaging clarity and measurement accuracy in actual measurement.

[0049] In one embodiment of the present invention, the measurement target refers to an area where specific parameters or features need to be detected and acquired during the measurement process in order to achieve high-precision measurement results. The measurement recipe in this embodiment includes PR area coordinates, AF area coordinates, and MB area coordinates. Among them, the PR area coordinates are used to specify a specific area for pattern recognition to ensure effective coordinate calibration and error correction operations in the area; the AF area coordinates are the area used for autofocus operations, and the selection of this coordinate will ensure the required imaging clarity for subsequent accurate measurement; the MB area coordinates represent the target area to be measured, and the system will perform actual measurement operations in this area. By integrating the coordinates of these three areas together, the measurement recipe forms a systematic workflow for the CDSEM measurement process, so that the measurement process can be performed efficiently and accurately.

[0050] In one embodiment of the present invention, based on the collected offset errors of all cargo transfer operations and the corresponding focus parameters during measurement, a process of generating an optimal compensation error and an optimal focus parameter includes: for each coordinate of a point to be measured, based on a feature point selection algorithm, according to the collected PR difference and MB difference of all cargo transfer operations, calculating a PR compensation value and an MB compensation value to generate the optimal compensation error; and calculating and generating the optimal focus parameter according to the PR compensation value, the PR difference of all cargo transfer operations and the autofocus parameter.

[0051] In one embodiment of the present invention, in a normal inspection process, the electron beam moves to the PR position of the i-th target according to the PR coordinates (Prxi, Pryi) in the preset recipe. However, due to the machine movement error and the electron beam drift error, the coordinates to be measured are actually moved to (pxi, pyi), resulting in an error between the two positions, which is marked as a PR offset. The calculation process of the PR offset is shown in Formulas 1 and 2. Then, an autofocus operation is performed on the PR coordinates after the offset correction, and the optimal focus condition is extracted.

[0052] PR-offsetxi=Prxi–pxi (Formula 1)

[0053] PR-offsetyi=Pryi-pyi (Formula 2)

[0054] In one embodiment of the present invention, based on the feature point selection algorithm, according to the collected PR difference and MB difference of all cargo handling operations, the process of calculating the PR compensation value and the MB compensation value includes: obtaining the PR offset (PR-offsetxi and PR-offsetyi) of each target and its related optimal focus condition (Afi) through multiple measurements, and using a linear fitting method to construct a functional relationship between the PR offset and the focus condition. Subsequently, with the help of a feature point selection algorithm, such as a median selection method or a Euclidean distance minimization method, the most representative PR coordinate (PR-Xi and PR-Yi) is calculated. Subsequently, the most representative PR coordinate is substituted into the linear fitting function to calculate the corresponding optimal focus condition.

[0055] Furthermore, in the process of generating the MB compensation value, the feature point selection algorithm is also used to extract the most representative MB coordinates (MB-Xi and MB-Yi) from all relevant MB offsets to ensure that the selected MB compensation value can truly reflect the characteristics and trends of the overall operation.

[0056] Furthermore, the feature point selection process includes but is not limited to: median selection method, Euclidean distance minimization method, mean selection method, density peak clustering method and weighted average method, etc. Among them, the median selection method reduces the impact of extreme values ​​on the results by calculating the median of the PR offset and enhances the robustness of the results; the Euclidean distance minimization method selects the PR coordinates that minimize the overall deviation based on the average distance between each data point, thereby improving the measurement accuracy; the mean selection rule provides a direct measure of the data center trend by calculating the average value of the measured data; the density peak clustering method selects the density peak as a representative feature point, which is suitable for complex data distribution; and the weighted average rule gives different weights according to the credibility and importance of the data points, thereby calculating the weighted average as the PR coordinate to improve the accuracy of the results.

[0057] In one embodiment of the present invention, the process of performing coordinate compensation operation on the to-be-measured point according to the optimal compensation error includes: substituting the PR compensation value, the MB compensation value and the coordinates of the to-be-measured point into a parameter compensation formula to generate a compensated measurement point.

[0058] In one embodiment of the present invention, the process of substituting the PR compensation value, the MB compensation value and the coordinates of the point to be measured into the parameter compensation formula to generate the compensated measurement point includes: first, substituting the PR compensation value, the MB compensation value and the coordinates of the point to be measured into the parameter compensation formula to generate the compensated measurement point. The specific steps include: first, moving the electron beam to the MB position. Since the size of the MB is usually very small (no more than 1 micron × 1 micron), even a slight deviation will have a significant impact on the measurement result. For this reason, fine tuning is further performed after performing the MB measurement. The process of fine tuning is consistent with the steps of measurement offset correction of the PR process, but has a large difference in execution granularity.

[0059] In one embodiment of the present invention, the MB fine-tuning compensation parameters are recorded as MB-offsetx and MB-offsety. During more than 10 product passes, the device records the PR offset (PR-offsetxi, PR-offsetyi) and MB offset (MB-offsetx, MB-offsety) of each target. By calculation, an optimal PR-Xi is found to minimize the Euclidean distance with multiple PR offset data. At the same time, the calculation of MB offset and Afi also needs to meet the conditions with PR-Xi, and finally the optimal compensation parameters, namely PR-Yi, MB-Xi, MB-Yi and Afi, are obtained. Finally, these calculated compensation data are applied to the measured coordinates (MBxi, MByi) of the corresponding target, and the parameter compensation formulas are shown in Formulas 3 and 4.

[0060]

[0061] By compensating and correcting the PR difference and the MB difference, the precise coordinates (MBXi, MBYi) of each point to be measured and the corresponding optimal focusing condition Afi are obtained, thereby ensuring the improvement of measurement accuracy and the consistency of results.

[0062] Step S23: performing a coordinate compensation operation on the point to be measured according to the optimal compensation error, and calling the optimal focus parameter to perform a simplified measurement operation on the coordinates of the point to be measured after the coordinate compensation operation.

[0063] In one embodiment of the present invention, the process of calling the optimal focus parameters to perform a simplified measurement operation on the coordinates of the point to be measured after the coordinate compensation operation includes: performing OM calibration and SEM calibration operations on the measurement site; measuring the coordinates of the point to be measured after the coordinate compensation operation based on the optimal focus parameters, and measuring the coordinates of the point to be measured after the coordinate compensation operation to generate a final measurement result.

[0064] It should be noted that OM calibration uses optical imaging technology to identify chip features through high-resolution lenses and image processing software, and is mainly used for preliminary calibration and to ensure the alignment accuracy of patterns; while SEM calibration generates high-resolution images by scanning samples with electron beams, which is suitable for high-precision calibration of tiny structures and complex shapes. The two complement each other, significantly improving the accuracy and efficiency of the semiconductor manufacturing process and ensuring the smooth progress of advanced processes.

[0065] In one embodiment of the present invention, after the coordinates of the points to be measured after the coordinate compensation operation are simplified, the following operation is also performed: in response to the occurrence of MB position loss during the measurement of multiple consecutive points to be measured, the conventional measurement operation is re-executed on the current point to be measured, and it is determined whether the measurement is successful; if the conventional measurement operation is unsuccessful after re-execution, multiple cargo transfer operations are re-executed according to the measurement sequence, and in each cargo transfer operation, the offset errors of all measurement points in the current cargo transfer operation and the corresponding focus parameters during measurement are collected; based on the offset errors of all the collected cargo transfer operations and the corresponding focus parameters during measurement, the optimal compensation error and the optimal focus parameters are re-generated; and the coordinate compensation operation is performed on the points to be measured according to the optimal compensation error generated again, and the simplified measurement operation is performed on the coordinates of the points to be measured after the coordinate compensation operation according to the optimal focus parameters generated again.

[0066] like Figure 3As shown, a schematic diagram of the process flow of CDSEM rapid measurement in one embodiment of the present invention. When a certain point to be measured after compensation cannot find the measurement frame MB in the measurement recipe and causes measurement failure, first use other successfully measured positions as new reference points to perform coordinate compensation measurement. If it still fails after compensation, use the conventional measurement process and continue to monitor the single-point measurement results. If there are multiple point failures in three consecutive Lots, an early warning will be triggered and the measurement status of the entire wafer will be marked as "failed", and subsequent measurement processes will be suspended. At this time, the engineer will intervene and analyze to determine whether the cause of the failure is a quality problem of the wafer itself, or whether the measurement compensation parameters need to be recalculated. The measurement compensation parameters can effectively deal with failures caused by the lack of a measurement box, and perform manual intervention when necessary, thereby improving the effectiveness of measurement quality control.

[0067] It should be noted that in the embodiments of the present application, words such as "exemplary" or "for example" represent examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0068] In the embodiments of the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can represent: a, b, c, ab, ac, bc or abc, where a, b, c can be single or multiple.

[0069] Figure 4 4 is a schematic block diagram of a CDSEM rapid measurement device 400 provided in an embodiment of the present application. Figure 4 As shown, the device includes a data acquisition module 401 , a parameter compensation module 402 and a simplified measurement module 403 .

[0070] The data acquisition module 401 is used to acquire the coordinates of a plurality of points to be measured at the measurement site, and generate a corresponding measurement sequence based on the coordinates of the points to be measured.

[0071] Parameter compensation module 402: used to perform multiple cargo transfer operations according to the measurement sequence, and collect the offset errors of all measurement points in the current cargo transfer operation and the corresponding focus parameters during measurement in each cargo transfer operation; based on the collected offset errors of all cargo transfer operations and the corresponding focus parameters during measurement, generate the optimal compensation error and the optimal focus parameters.

[0072] The simplified measurement module 403 is used to perform a coordinate compensation operation on the point to be measured according to the optimal compensation error, and call the optimal focus parameter to perform a simplified measurement operation on the coordinates of the point to be measured after the coordinate compensation operation.

[0073] It should be understood that the specific process of each module executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0074] It should also be understood that the division of modules in the embodiments of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present application may be integrated into a processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0075] Figure 5 is a schematic block diagram of an electronic terminal provided in an embodiment of the present application. Figure 5 As shown, the electronic terminal includes: at least one processor 501, a memory 502, at least one network interface 503 and a user interface 505. The various components in the device are coupled together through a bus system 504. It can be understood that the bus system 504 is used to realize the connection and communication between these components. In addition to the data bus, the bus system 504 also includes a power bus, a control bus and a status signal bus. However, for the sake of clarity, Figure 5 In the specification, various buses are labeled as bus systems.

[0076] The user interface 505 may include a display, a keyboard, a mouse, a trackball, a click gun, keys, buttons, a touch pad or a touch screen.

[0077] It is understood that the memory 502 can be a volatile memory or a non-volatile memory, and can also include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), synchronous static random access memory (SSRAM). The memory described in the embodiments of the present invention is intended to include but is not limited to these and any other suitable categories of memory.

[0078] The memory 502 in the embodiment of the present invention is used to store various types of data to support the operation of the electronic terminal 500. Examples of these data include: any executable program used to operate on the electronic terminal 500, such as an operating system 5021 and an application 5022; the operating system 5021 includes various system programs, such as a framework layer, a core library layer, a driver layer, etc., for implementing various basic services and processing hardware-based tasks. The application 5022 can include various applications, such as a media player (Media Player), a browser (Browser), etc., for implementing various application services. The CDSEM fast measurement method provided in the embodiment of the present invention can be included in the application 5022.

[0079] The method disclosed in the above embodiment of the present invention can be applied to the processor 501, or implemented by the processor 501. The processor 501 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit in the processor 501 or the instruction in the form of software. The above processor 501 may be a general processor, a digital signal processor (DSP, Digital Signal Processor), or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The processor 501 can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiment of the present invention. The general processor 501 may be a microprocessor or any conventional processor, etc. In combination with the steps of the accessory optimization method provided in the embodiment of the present invention, it can be directly embodied as a hardware decoding processor to execute, or it can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium, which is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0080] In an exemplary embodiment, the electronic terminal 500 may be implemented by one or more application specific integrated circuits (ASIC), DSP, programmable logic device (PLD), complex programmable logic device (CPLD) to execute the aforementioned method.

[0081] According to the method provided in the embodiments of the present application, the present application also provides a computer program product, which includes: computer program code, when the computer program code is run on a computer, the computer executes the CDSEM rapid measurement method of any embodiment shown in the above embodiments.

[0082] According to the method provided in the embodiments of the present application, the present application also provides a computer-readable storage medium, which stores a program code. When the program code runs on a computer, the computer executes the CDSEM rapid measurement method of any embodiment shown in the above embodiments.

[0083] The terms "component", "module", "system", etc. used in this specification are used to represent computer-related entities, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program and / or a computer. By way of illustration, both applications running on a computing device and a computing device can be components. One or more components may reside in a process and / or an execution thread, and a component may be located on a computer and / or distributed between two or more computers. In addition, these components may be executed from various computer-readable media having various data structures stored thereon. Components may, for example, communicate through local and / or remote processes according to signals having one or more data packets (e.g., data from two components interacting with another component between a local system, a distributed system and / or a network, such as the Internet interacting with other systems through signals).

[0084] Those of ordinary skill in the art will appreciate that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0085] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0086] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0087] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0088] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0089] In the above embodiments, the functions of each functional unit can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions (programs). When loading and executing computer program instructions (programs) on a computer, the process or function according to the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions can be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server, data center, etc. that contains one or more available media integrated. Available media may be magnetic media (e.g., floppy disks, hard disks, tapes), optical media (e.g., high-density digital video discs (DVDs), or semiconductor media (e.g., solid state disks (SSDs)).

[0090] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0091] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0092] In summary, the present application provides a CDSEM rapid measurement method, device, medium, program product and terminal. The present invention provides a method for improving the CDSEM measurement efficiency, and optimizes the CDSEM measurement process by introducing technical means of measurement position compensation and preset autofocus voltage value. The specific steps include: obtaining the coordinates of multiple points to be measured, generating a measurement sequence based on these coordinates, and performing multiple cargo transfer operations. In each cargo transfer operation, the offset errors and current focus parameters of all measurement points are collected, the optimal compensation error and the optimal focus parameters are generated, and the optimal compensation error and the optimal focus parameters are applied to coordinate compensation and simplified measurement operations. The present invention significantly improves the efficiency and accuracy of the CDSEM measurement system, especially effectively meets the needs of fast and accurate measurement in the mass production stage. Thereby avoiding the repeated calibration and focusing steps in traditional CDSEM measurement, greatly reducing the measurement time, and enhancing the consistency and reliability of the operation. Therefore, the present application effectively overcomes the various shortcomings in the prior art and has a high industrial utilization value.

[0093] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A CDSEM rapid measurement method, characterized in that: include: Acquire coordinates of multiple points to be measured at the measurement site, and generate corresponding measurement sequences based on the coordinates of the points to be measured; Perform multiple cargo transfer operations according to the measurement sequence, and collect the offset errors of all measurement points in the current cargo transfer operation and the corresponding focus parameters during measurement in each cargo transfer operation; Generate the optimal compensation error and optimal focus parameters based on the collected offset errors of all cargo handling operations and the corresponding focus parameters during measurement; A coordinate compensation operation is performed on the point to be measured according to the optimal compensation error, and a simplified measurement operation is performed on the coordinates of the point to be measured after the coordinate compensation operation by calling the optimal focus parameter.

2. The CDSEM rapid measurement method according to claim 1, characterized in that: The process of collecting the offset errors of all coordinates of the points to be measured and the corresponding optimal focus parameters in each cargo transfer operation includes: Performing machine error correction and pattern recognition operations on the coordinates of the current point to be measured to generate the coordinates of the calibration point; calculating and generating a PR difference value based on the coordinates of the calibration point and the coordinates of the current point to be measured; Performing an auto-focus operation on the calibration point coordinates, and extracting auto-focus parameters after the auto-focus operation; Based on the measurement recipe, the electron beam is focused to the MB region of the coordinates of the current point to be measured, and the MB difference value used to characterize the center error between the MB region and the coordinates of the point to be measured is calculated.

3. The CDSEM rapid measurement method according to claim 2, characterized in that: Based on the collected offset errors of all cargo handling operations and the corresponding focus parameters during measurement, the process of generating the optimal compensation error and the best focus parameters includes: For each coordinate of the point to be measured, based on the feature point selection algorithm, according to the collected PR difference and MB difference of all cargo transfer operations, the PR compensation value and the MB compensation value are calculated to generate the optimal compensation error; The optimal focus parameters are calculated and generated according to the PR compensation value, the PR difference values ​​of all cargo transfer operations and the auto focus parameters.

4. The CDSEM rapid measurement method according to claim 3, characterized in that: The process of performing coordinate compensation operation on the to-be-measured point according to the optimal compensation error includes: substituting the PR compensation value, the MB compensation value and the coordinates of the to-be-measured point into a parameter compensation formula to generate a compensated measurement point.

5. The CDSEM rapid measurement method according to claim 1, characterized in that: include: The process of calling the optimal focus parameter to perform a simplified measurement operation on the coordinates of the point to be measured after the coordinate compensation operation includes: performing OM calibration and SEM calibration operations on the measurement site; The coordinates of the to-be-measured point after the coordinate compensation operation are measured based on the optimal focus parameter, and the coordinates of the to-be-measured point after the coordinate compensation operation are measured to generate a final measurement result.

6. The CDSEM rapid measurement method according to claim 1, characterized in that: After the coordinate compensation operation is performed on the coordinates of the point to be measured, the following operations are performed: In response to the occurrence of MB position loss during the process of performing measurement on a plurality of consecutive points to be measured, re-performing a conventional measurement operation on the current point to be measured, and determining whether the measurement is successful; If the conventional measurement operation is not successful after re-execution, multiple cargo transfer operations are performed again according to the measurement sequence, and the offset errors of all measurement points in the current cargo transfer operation and the corresponding focus parameters during measurement are collected in each cargo transfer operation; based on the collected offset errors of all cargo transfer operations and the corresponding focus parameters during measurement, the optimal compensation error and the optimal focus parameters are generated again; A coordinate compensation operation is performed on the point to be measured according to the regenerated optimal compensation error, and a simplified measurement operation is performed on the coordinates of the point to be measured after the coordinate compensation operation according to the regenerated optimal focusing parameter.

7. A CDSEM rapid measurement device, characterized in that: include: Data acquisition module: used to acquire the coordinates of multiple points to be measured at the measurement site, and generate a corresponding measurement sequence based on the coordinates of the points to be measured; Parameter compensation module: used to perform multiple cargo transfer operations according to the measurement sequence, and collect the offset errors of all measurement points in the current cargo transfer operation and the corresponding focus parameters during measurement in each cargo transfer operation; based on the collected offset errors of all cargo transfer operations and the corresponding focus parameters during measurement, generate the optimal compensation error and the optimal focus parameter; Simplified measurement module: used to perform coordinate compensation operation on the point to be measured according to the optimal compensation error, and call the optimal focus parameter to perform simplified measurement operation on the coordinates of the point to be measured after the coordinate compensation operation.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the CDSEM rapid measurement method according to any one of claims 1 to 6 is implemented.

9. A computer program product, characterized in that The computer program product includes computer program codes, and when the computer program codes are executed on a computer, the computer is enabled to implement the CDSEM rapid measurement method according to any one of claims 1 to 6.

10. An electronic terminal comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the CDSEM rapid measurement method according to any one of claims 1 to 6.

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